Freediving in the St. Lawrence River?

I've been freediving in the River a few times. The current is the biggest problem, especially in the Brockville/Prescott area's above the Dam. Visibility is usually good, 10+ meters, at least I think that is good Temperature varies seasonally of course. By July it should be in the 20C range, right now it's about 6 C.

A good temperature reference is here:

http://www.ndbc.noaa.gov/station_page.php?station=aban6

This is a weather station across the river at Alexandria Bay, NY.

If you jump of the Prescott dock you can usually find numerous fish, including some scary big Carp. Their are several ship wrecks close to shore that you can freediver, but again the current is an issue. It's not so fast that you can't kick against it but it will push you down stream quickly on a fast running day.

I should add that their are TONS of good lakes to dive in without the current issue (or boat for that matter). Any of the Provincal park Lakes are good, though not particularily deep (except Bon Echo which goes down to over 100m I'm told).

Hope that helps.